1. Field of the Invention
This invention relates to copy finishers for assembling copies into booklets, for stapling the booklets, if desired, and for stacking the booklets in a straight or offset manner in an output tray.
2. Description of the Prior Art
Copy processing devices, such as copy finishers, for processing copies made by reproduction apparatus are known in the art. Thus, U.S. Pat. No. 3,630,607 discloses a xerographic reproducing machine including document handling apparatus which recirculates a set of originals to an exposure platen of a xerographic copier, a copier for producing a series of copies corresponding to the set of originals and a copy finisher for assembling the copies into sets in an intermediate tray assembly, for offsetting alternate sets by means of a set separation assembly and for ejecting the sets into an output tray where they are stacked in staggered, i.e., offset, manner. U.S. Pat. Nos. 3,671,094; 3,682,328; 3,685,712; 3,690,537 and 3,709,595 disclose a xerographic processor including a recirculating document feeder, a xerographic copier and a copy finisher which functions either to assemble copies into booklets for stapling in an intermediate tray assembly before straight stacking the stapled booklets in an output tray or to offset stack copy sets in the output tray by causing individual copies to bypass the intermediate tray assembly and to be individually offset stacked in sets in the output tray by means of a paddle wheel assembly. U.S. Pat. Nos. 3,902,709 and 3,908,978 disclose binless sorters used with xerographic copiers which produce uncollated copies, the sorters having output trays which may be reciprocated in order to offset stack copy sets produced by the sorter. U.S. Pat. No. 3,946,879 discloses a device for stacking bundles of paper crosswise in an output hopper.
Although the various copy processing devices disclosed in the aforementioned patents may have been appropriate for their intended uses, certain deficiencies thereof may be noted. Where copies are assembled in an intermediate tray before offset stacking, such as is disclosed in U.S. Pat. No. 3,630,607, no provision is made for situations where the number of copies to be offset stacked in the output tray is greater than the copy assembling limit of the intermediate tray. Such assembling capacity thus limits the usefulness of such copy finisher when it would be desirable to offset stack larger sets of copies. In addition, if a malfunction, such as a paper jam, should occur in the copier in conjunction with which the copy finisher is operating, it would be desirable to be able to identify the copy set in progress in the finisher output tray since such set may be either incomplete or include mangled sheets. None of the aforementioned patents disclose such capability.